What is the icon you are you using? (So what's the code for your discord icon)
On top of that, where are you loading this ?
Since you only added the JS did you remove the old CSS / SCSS and added the new ones ?

Looks to me with the first error you are missing some columns in your database or you upgraded with a theme that's not compatible.
I would suggest rollback your backup.
And reset the theme, also re-download and make sure there are no corrupt files.
Move old files except uploads folder to a temp folder, then upload and upgrade

This is very simple chat system with the basic features:
Ajax chat, auto update.
Display as IPS widgets, so you can place it in sidebar or top page.
Sound notification. User can toggle on/off.
Block users.
Announcement (on Top or Tab).
Supports emoticons, URL, Image URL (gif, png, jpg)
Supports GIPHY
Supports youtube.
@mention by clicking on usernames.
Flood control.
Time format.
Display newer messages in top or bottom.
Permissions for viewing, chatting & management.
Edit/Delete messages.
Fixes:
Disconnect when posting youtube url.
Chatbox doesn't load if there are a lot of messages.